Question

Essentially I am looking for a PHP function or equation that will output the Matrix values used in SVG transform.

I have hunted high and low and unfortunately have found nothing.

I am well aware of the rotate() and scale function() however these are not what I am in need of.

I need to be able to take a rotation angle in degrees along with x/y scale data and output a series of values in SVG transform format matrix(a,b,c,d,e,f)

Ideally I would like to be doing this in PHP but as stated, a standard mathematical equation would help also.

Hopefully someone can point me in the right direction.

Answer 1

You can compute the values by multiplying the matrices of the single transformations. Have a look in the SVG specification to find their definition:

rot(a)       := matrix(cos(a), sin(a), -sin(a), cos(a), 0, 0)
scale(sx,sy) := matrix(sx, 0, 0, sy, 0, 0)

Depending on the order the transformations should be applied (rotation before scaling vs. scaling before rotation), you get different matrices:

rot(a)*scale(sx,sy) = matrix(sx*cos(a), sx*sin(a), -sy*sin(a), sy*cos(a), 0, 0)
scale(sx,sy)*rot(a) = matrix(sx*cos(a), sy*sin(a), -sx*sin(a), sy*cos(a), 0, 0)